<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>多列布局</title>
  <style>
    body {
      margin: 0;

    }

    .lanmu {
      margin: 0 auto;
      width: 1420px;
      /* height: 1000px; */
      background-color: greenyellow;
      /* padding: 30px; */
      overflow: hidden;

    }

    .lanmu .pro {
      float: left;
      /* width: 300px; */
      height: 500px;
      /* background-color: khaki; */
      margin: 10px;
    }

    .lanmu .pro:nth-child(1) {
      width: 20%;
      background-color: khaki;
    }

    .lanmu .pro:nth-child(2) {
      width: 30%;
      background-color: lightcoral;
    }

    .lanmu .pro:nth-child(3) {
      width: 40%;
      background-color: lightcyan;
    }
  </style>
</head>

<body>
  <div class="lanmu">
    <div class="pro">
      <div>

      </div>
      <div>

      </div>
    </div>
    <div class="pro"></div>
    <div class="pro"></div>
  </div>
</body>

</html>